Green Bean and Potato Salad

This years my contribution to our Easter dinner is Green Bean and Potato Salad. The ingredients are easily found in the season of no-fresh veggies from the garden. It complements the ham quite well.
Here's my recipe:
2 lb. cut frozen green beans;
4 Yukon gold potatoes, cut into 1/2" cubes;
1/2 medium sized onion, finely chopped;
1 large lemon, juice and zest;
1/2 C. Olive oil;
2 t. stone ground mustard;
1 T. fresh thyme, finely chopped;
2 T. fresh parsley, finely chopped;
3 large cloves of garlic, minced;
1 T. caper, chopped;
Salt, pepper  and sugar to taste.
Optional: Kalamata olives and cubed feta cheese
Method:
Bring a large pot of water to a boil. Blanch green beans. After removing the green beans, using the same water, cook the potatoes until tender to the bite. Remove.
For the dressing: combine all ingredients except the green beans and potatoes. Pour the dressing over the green beans and potatoes. Allow flavor to set in for at least 2 hr. before serving.